Lamp base



FIG. 1 is a perspective view of the lamp base comprising my new design;

FIG. 2 is an elevational view of one side of my lamp base design, all other sides being identical thereto; and,

FIG. 3 is a top plan view of my lamp base design.

The broken lines shown in FIG. 2 are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a lamp base, as shown and described. 